docjl61

Nicely done. Looks like Stablebit Scanner has more sorting options than Hard Disk Sentinel.

You can use the Disk Management panel in Windows to add/change/remove the letters of your drives.
Because you're swapping the letters, you may need to restart your PC between operations (e.g. remove letters, restart, add letters); so first take note of the physical disk numbers for each pool drive (normally displayed in the lower half of the panel) so you add the correct letter to the correct drive afterwards.
(obviously, do NOT mess with the drive letter of your operating system drive)

Well, there may be some scenario where drive letters are required. But with 16 HDDs in my pool, I am more than happy to assign names to the HDDs and not have to bother with drive letters. In theory, DrivePool is able to pool many more than 26 HDDs, so you would reach a point where you would run out of drive letters anyway.
If you need to assign a drive letter to a DrivePool HDD that has a name only, you can easily do that in Disk Management and it will not affect DrivePool at all. Again, DrivePool does not read the drive letter at all. It only uses the hidden PoolPart directory for identification.
As mentioned, you may have to restart your computer if you decide to reassign drive letters to your DrivePool HDDs, not for DrivePool itself, but sometimes other Windows program will not recognize the newly named drive without a restart. IIRC, Disk Management will warn you about that when you change/add/remove a drive letter.

FWIW, I just removed all drive letters from my DrivePool HDDs. DrivePool does not need a drive letter to recognize a HDD in the pool. It uses the hidden PoolPart directory.
Removing drive letters on the HDDs makes a less cluttered display in Windows 10 File Explorer as it will only show HDDs with drive letters. That works great for me as I currently have 16 HDDs in my DrivePool. Those HDDs are dedicated to DrivePool and nothing else. So I don't need any drive letters assigned to them.
Of course, when you remove the drive letters, Windows 10 File Explorer can longer "see" the drive normally. You would have to go back into Disk Management and reassign a drive letter.
I track all my pool HDDs by name, such as DP01, DP02, DP03, etc.... which also corresponds to the physical location on my rack. I also put the drive name sticker on the physical drive/case for easy identification. The HDDs in my pool do not have drive letters assigned to them, as I stated. The DrivePool UI lists the names all in alphabetic order, which is very nice. However, if for some reason I want to reassign a drive letter to a particular drive, I just use Disk Management and look up the HDD by name. That is much easier then trying to track all the S/N of the HDDs.
I am not using Scanner, so I am not sure if that program requires drive letters to work. Is there some reason you need/want to keep any drive letters assigned to your pool HDDs? I found DrivePool was easier to work with when I removed all those drive letters from my pool HDDs. Just my thoughts to your initial question on how to not drive yourself crazy with numerous drives in DrivePool.

I just removed the letters on all 8 pool drives and nothing exploded!
Same for SB scanner, business as usual (except for now blank drive letters
 
You now have me interested in leaving them unlettered, but there must be a scenario/usage case where lettered pool drives are desirable.
EDIT:
Should a need arise, I could always revert to letters, but I'll leave them out for now and see how it goes.
Thanks @gtaus

Yeah, old habits... When I removed the drive letters and just used drive names, life with DrivePool became easier with my 16 HDDs. It works better for me.

This sounds like good news to me
I think when I started using drivepool, individual drives were "letter-less" (file explorer would only show pool drives, and non-pooled OS drive also, obviously)..
For a specific reason I fail to remember (lets call it old habits), I switched to lettering and never looked back once.
Thanks !

The title is taken from the user manual.
Indeed I combined 3 hard drives in my pool, but when I click on it in Windows Explorer, its empty.
 
I should eventually see those files appearing in the drivepool, right?
 
You must have seen this question a million time already, sorry about that

did the drives have files on before you combined them into the pool?
 
if so you need to move the files into the poolpart (hidden) directory on the drives then they will appear in the pool